Xolotl is an open source "harmonic" synthesiser built with HISE. Plugins are available for Mac OS , Windows and Linux.
The “oscillator" consists of up to 32 independently pitched waveforms. These can be standard synth waveforms, multi-samples (expanded version only) or single cycle waveforms (expanded version only). By default the pitch increments through the harmonic series, but can be un-quantised using the step knob..
32 waveforms need at least 32 sample and hold effects, right? maybe not under normal circumstances, but this one's a bit different. Depending on how it’s configured, it can act as an effect, sound generator or modulator.
A bunch of filters with independent control of the cutoff. There's a ton of sonic potential here. Comb filtering, phaser effects and some very tasty interaction between the S&H section.
At the end of the signal chain is simple ADSR envelope and pan spread control.
Xolotl has 2 looping envelopes & 3 over-spec’d LFOs with mixable waveforms and unique waveshaper